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Stanford University

Stanford University

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Stanford University

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  1. Stanford University Global Climate & Energy Project Sept, 2008 Biomass Energy: the Climate Protective Domain Chris Field cfield@ciw.edu http://dge.ciw.edu

  2. Constraints Food Fuel Fossil offsets Other emissions Energy Nature

  3. Climate-protective biofuels • Grow more plants • Without more environmental downsides • Get more energy per unit of plant biomass • Figure out where it does and doesn’t make sense to produce biofuels

  4. Energy in ag and pastures? Global Primary Energy = 480 EJ/y * In ½ biomass (to allow for roots), assume 45% C

  5. Will yields increase dramatically? • Historical trends – a century of success • 1-2%/y for major crops • Will this continue? • Can it accelerate?

  6. Ag yields – a century of successincreases of 1-2% y-1 Lobell and Field ERL 2007

  7. Extracting climate sensitivity • First difference yield • Define locally-weighted climate • Regress against • Growing season tmax, tmin, precip • Define growing season based on explained variance • Reconstruct trend with (observed) and without (climate corrected) climate

  8. Lobell and Field ERL 2007

  9. Global area, production, and yield changes for six major world crops

  10. Lobell and Field ERL 2007

  11. Ag in relation to natural NPP • Ag/NPP -- Globally about 65% • Global average crop yields unlikely to exceed natural NPP for at least the next several decades

  12. Field, Campbell, Lobell TREE 2008

  13. Field et al TREE 2008

  14. Potential from abandoned land Campbell et al ES&T 2008

  15. From available abandoned land 1.6 – 2.1 Pg C x 2 g Plant/g C x 0.5 g top/g plant x 20 EJ/Pg = 32 - 41 EJ = 7-8% of current global energy system

  16. Bioenergy • Climate impact depends on pre-existing ecosystem • Indirect as well as direct paths to carbon loss • Natural NPP reasonable proxy for potential yield under ag management • Available land resource limited • Quantity and quality • Big potential in absolute terms • But a small slice of present or future demand

  17. Biomass energy:the climate protective domain • Food/Biomass energy interactions • Roz Naylor, Holly Gibbs • Biomass in areas converted to bioenergy • Greg Asner, Scott Loarie • Albedo feedbacks from bioenergy agriculture • David Lobell, Matt Georgescu • Available land, potential yield, GHG balance • Chris Field, Elliott Campbell

  18. Future energy needs:Many times current

  19. Biomass energy • Corn $190/ton • Coal Power River $15/ton Central Appalachia $149/ton • Crude oil $820/ton

  20. Ferment or burn?

  21. Understanding deforestation • Where is it occurring? • Where will it occur in the future? • What are the drivers?

  22. PRODES deforestation matches low biomass from RADAR PRODES not forested, 2000 RADAR low biomass, 2000

  23. Large-scale patterns:Kernel approach to deforestation rate fraction low biomass, 2000 fraction not forested, 2000

  24. Year-by-year deforestation Pre-deforestation biomass (Mg ha-1)

  25. Greater biomass in remaining forests